Decolorization and degradation of cationic red X-GRL by upflow blanket filter

An anaerobic upflow blanket filter (UBF) was employed for the treatment of dye wastewater containing cationic red X-GRL (X-GRL) in this study. The bacterial community in the UBF at its stable state was investigated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that all color and the majority of chemical oxygen demand (COD) (92–74%) can be removed as the dye load increased from 33 to 134 g/(m³ d). The removal of color and COD were mostly attributed to the anaerobic activated sludge in the reactor. According to the DGGE fingerprints, the bacterial community in the biofilm was more diverse than that in the activated sludge. The bacterial diversity of the activated sludge and the bioflim both decreased with the dye load increasing. The dominant group was found to be phyla proteobacteria including β-proteobacteria, γ-proteobacteria, δ-proteobacteria and ɛ-proteobacteria, suggesting that these microbes might play an important role in X-GRL decolorization and degradation.